Vehicle interference prevention device

ABSTRACT

There is provided a vehicle interference prevention device that, by computing a range of possible locations of a vehicle taking into consideration the time at which the location of the vehicle is measured, can safely predict the location of the vehicle, even with minimal frequency of radio contact, and prevent interference among unmanned vehicles or manned vehicles over the entirety of large work site, An unmanned vehicle uses the latest position data for a manned vehicle acquired (received) via an inter-vehicle communication device to determine a position (position at a certain point in time) as the basis for computing a circle having this position as its center and having a radius equal to the distance traveled at maximum speed from this point to a predetermined future point in time, and designates the area within this circle on a prearranged travel route as a range of possible locations for the manned vehicle. The unmanned vehicle then decides whether its own vehicle position interferes with this circle.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a vehicle interferenceprevention device for preventing vehicles from interfering with oneanother in situations where a plurality of vehicles are traveling overtravel routes.

[0003] 2. Description of the Related Art

[0004] At large work sites such as rock quarries and mining operations,control of a plurality of unmanned vehicles, such as unmanned dumptrucks, used to perform operations such as hauling earth is typicallyaccomplished through a vehicle monitoring system in which a monitoringstation is set up as a base station, with all of the unmanned vehiclesbeing managed and monitored by this monitoring station.

[0005] Vehicle monitoring systems of this type known in the art includethe systems disclosed in Japanese Patent Application Laid-Open No.63-150710 (hereinbelow referred to as Document 1) and Japanese PatentApplication Laid-Open No. 10-69599 (hereinbelow referred to as Document2), as well as in the Applicant's co-pending Japanese Patent ApplicationNo. 9-27960 (hereinbelow referred to as Document 3), Japanese PatentApplication No. 9-36324 (hereinbelow referred to as Document 4), andJapanese Patent Application No. 9-86612 (hereinbelow referred to asDocument 5).

[0006] According to the system disclosed in Citation 1, there isprovided a predetermined operation whereby, in the event of a risk ofcollision between any of a plurality of unmanned vehicles, the unmannedvehicles at risk for collision may exchange necessary information witheach other via communication devices so as to avoid collision.

[0007] According to the system disclosed in Citation 2, lane-changesensors provided with optical means are embedded in the road surface ofa highway at the boundary between an automatically guided vehicle laneL1 and an adjacent travel lane L2, so that in the event that a vehicletraveling in lane L2 should enter lane L1 (i.e., make a lane change) thecontrol system on the basis of signals from the lane-change sensors,will control any automatically guided vehicle traveling behind thevehicle which has entered the lane in such a way as to provide greaterdistance between vehicles.

[0008] According to the system disclosed in Citation 3, long-range (e.g.VHF) communication devices are provided to a plurality of unmannedvehicles and to a monitoring station, the plurality of unmanned vehiclesbeing provided also with short-range (e.g. SS transmission)communication devices, whereby travel instruction data may betransmitted from the monitoring station to the unmanned vehicles via thelong-range communication devices, while the unmanned vehicles mayexchange vehicle position data among themselves using the short-rangecommunication devices, thereby allowing for monitoring of positionalrelationships among the vehicles.

[0009] According to the system disclosed in Citation 4, an arrangedroute of travel is divided into a plurality of segments, and a pluralityof vehicles, via communication devices provided thereto, transmit to amonitoring station vehicle position data and the like which has beenascertained by position-measuring devices, transmitting this informationeach time that a vehicle reaches a segment boundary on an arranged routeof travel, whereby the monitoring station may ascertain positionalrelationships among a plurality of vehicles in each segment, and monitorand control the plurality of vehicles with reference to these positionalrelationships. In order to prevent interference between manned vehiclesand unmanned vehicles, for example, the monitoring station will forciblyhalt or decelerate a manned vehicle in the event that the manned vehicledoes not obey instruction data (data instructing deceleration, a stop,etc.).

[0010] According to the system disclosed in Citation 5, vehicle positiondata is exchanged via communication devices among a plurality ofvehicles, for example, manned vehicles and unmanned vehicles, wherebyvehicles, on the basis of vehicle position data for other vehicles,perform control so as to prevent interference among vehicles. In thissystem, in the event of a determination, made on the basis of vehicleposition data exchanged between a manned vehicle and an unmannedvehicle, that the vehicles are interfering with one another, control iseffected such that the unmanned vehicle comes to an emergency stop whilethe manned vehicle is decelerated so as to prevent interference amongthe vehicles.

[0011] The systems disclosed in Citation 1 and Citation 3, however, aredirected to preventing interference among unmanned vehicles and make nomention whatsoever of preventing interference among manned vehicles andunmanned vehicles.

[0012] The system disclosed in Citation 2 employs a stationaryinstallation (i.e. a highway), detecting vehicles entering the lanetraveled by automatically guided vehicles and decelerating theautomatically guided vehicles. However, the use of a stationaryinstallation entails numerous initial outlays associated withconstruction of the installation. Further, it is difficult to adapt sucha system to a mine, where travel routes change frequently.

[0013] While it is possible to embed lane change sensors along thecourse of an asphalt highway, this approach is not feasible for mineroads, which are maintained by graders.

[0014] Specifically, the off-road dump trucks used in mining operations,even those of ordinary size, have vehicle weights of several hundredtons when loaded, while larger vehicles can weigh in at close to 700tons. Even if lane change sensors were embedded in an asphalt travelpath (roadway), the asphalt road would not be able to bear the weight ofthe vehicle. Also, lane change sensors embedded in the roadway would becrushed by the weight of the vehicle.

[0015] Accordingly, it is common practice in milling operations and thelike to pave roads with gravel. Assuming that lane change sensors wereembedded in road paved with gravel or the like, the need to periodicallymaintain the pavement through grading poses the problem of equipment,such as lane change sensors, embedded in the pavement being crushedduring the grading operation.

[0016] Further, lane change sensors can detect a vehicle only after ithas entered a lane; while this presents no particular problem in thecase of highways and other roadways with minimal cross-traffic, inmining operations, which typically have a complex web of routes, thereexists a risk, depending on the condition of travel of a vehicle, thatthe vehicle will be detected only as it approaches an intersection. Thismeans that where the risk exists that traveling vehicles will interfere(collide) in proximity to an intersection, the delay in control toprevent collision may result in collision of the vehicles.

[0017] The system disclosed in Citation 4 assumes travel of mannedvehicles over a predetermined course (prearranged travel route) in amanner analogous to unmanned vehicles, with monitoring and control beingperformed from a central monitoring station, and as such is difficult toimplement in situations where the human operator of a vehicle maychoose, for example, to make a U-turn mid-course or otherwise changecourse from time to time. Further, manned vehicles are driven by humanoperators, and some operators may find disagreeable the approach oftravel to a predetermined destination selected in accordance with theoperation. Forcible introduction of a system that ignores operatorpreference will have a negative impact on operations.

[0018] According to the system disclosed in Citation 5, interferenceamong vehicles may be prevented even in situations where manned vehiclescoexist with unmanned vehicles. However, depending on communicationconditions, it may occur that an unmanned vehicle cannot receive vehicleposition data from a manned vehicle; in such instances, there exists therisk of a delay in the determination process for interference betweenvehicles, resulting in an inability exercise proper control to preventinterference between vehicles.

[0019] For manned vehicles, in instances of interference betweenvehicles, while a Reduce Speed command sent from the unmanned vehicle isdisplayed on the display screen of a display device, it is not possibleto ascertain the positional relationship vis-á-vis the other vehicle.That is, if the position of one's vehicle relative to the other vehiclecould be displayed in real time, it would be possible to determinebefore the fact if a given current course of travel is likely to resultin interference between vehicles, for example, thereby making itpossible to avoid interference between vehicles. This is not possiblewith the system disclosed in Citation 5, however.

[0020] The systems disclosed in Citation 1 and Citations 3 to 5 presumethat position-measuring devices and communication devices are providedto all vehicles (both unmanned vehicles and manned vehicles) operatingin a large work site such as a mining operation, but providingposition-measuring devices and communication devices to all vehiclesrequires a significant initial outlay. There are also various costsassociated with equipping vehicles that do not enter the mine, such asrepair vehicles, with position-measuring devices and communicationdevices.

[0021] Position-measuring devices and communication devices that areused infrequently have increased likelihood of malfunction when it isattempted to operate the device. While it is possible to designposition-measuring devices and communication devices to be readilyattachable and detachable, in some instances there may be aninsufficient number of devices.

[0022] From the standpoint of preventing vehicle interference, that is,for reasons of vehicle safety, vehicles lacking position-measuringdevices and communication devices due to malfunction or a shortagethereof cannot be employed. This means that despite the availability ofvehicles to do the work, the vehicle resources cannot be usedeffectively.

[0023] In the vehicle monitoring systems of the Citations cited above,the radio waves used for communications of the short-range (e.g. SStransmission) communication devices used for communication amongvehicles can only travel over short distances (from 100 m to 1 km), andin large-scale mining operations involving large distances betweenvehicles and large numbers of vehicles (50 to 100, for example), it isnot possible for all vehicles to know the current positions of othervehicles.

[0024] With the conventional vehicle monitoring systems described above,while long-range (10 km to 20 km) communications are possible iflong-range (e.g. VHF) communication devices are used, slow transmissionspeed (9600 bps) creates the problem of inability to constantly beapprised of the current locations of a multitude of vehicles. Sincelarge amounts of data are transmitted to the monitoring station from themultitude of vehicles, the volume of data being transmitted is quitelarge. Since the communications format entails slow transmission speeds,the communications circuit becomes complicated and the communicationscircuit becomes overloaded, resulting in inability in actual practice tomanage and monitor vehicles.

[0025] Where it is attempted to address this problem by employingshort-range communication devices capable of higher transmission speeds(256 kbps) for communication among vehicles, while it becomes possibleto transmit very large amounts of data rapidly, the limited range of theradio waves makes it impossible to provide full communications coverageover the entirety of large work site. Thus, of the vehicles spread overentirety of a large work site, it will not be possible for a vehicle tocommunicate with another vehicle located a distance away that exceedsthe short range transmission range (100 m to 1 km, for example), andhence there will be no way to determine the current position of thisother vehicle.

[0026] Accordingly, in large-scale mining operations involving largedistances between vehicles and large numbers of vehicles, it has notbeen possible for all vehicles lo be constantly apprised of the currentlocations of other vehicles.

[0027] With the foregoing in view, it is an object of the presentinvention to provide a vehicle interference prevention device that, bycomputing a range of possible locations of a vehicle taking intoconsideration the time at which the location of the vehicle is measured,can safely predict the location of the vehicle, even with minimalfrequency of radio contact, and prevent interference among unmannedvehicles or manned vehicles over an entire large work site.

SUMMARY OF THE INVENTION

[0028] According to the invention of claim 1, the object is achievedthrough a vehicle interference prevention device for preventinginterference among vehicles where a plurality of vehicles are travelingover a travel route, wherein each of the plurality of vehiclescomprises:

[0029] measuring means for measuring a position of its own vehicle;

[0030] communication means for exchanging with other vehicles, in awireless communications format, position information indicating theposition of its own vehicle, as measured by the measuring means;

[0031] estimating means for estimating a likelihood of interferencebetween its own vehicle and other vehicle on the basis of positioninformation for the other vehicle received via the communication means,time information indicating a reception time at which the positioninformation is received, and the position information for its ownvehicle; and

[0032] control means for performing a preset control routine in theevent that interference is predicted by the estimating means, so as toavoid interference with the other vehicle.

[0033] According to the second invention, in the vehicle interferenceprevention device of the first invention,

[0034] the communication means comprises:

[0035] means for transmitting and receiving vis-á-vis other vehicles, ina wireless communications format, position information indicatingvehicle position, as measured by its own measuring means, and timeinformation indicating a time of measurement of the vehicle position ortime information indicating a time of transmission of the positioninformation; and

[0036] the estimating means comprises:

[0037] means for estimating the likelihood of interference between itsown vehicle and other vehicle on the basis of the position informationfor the other vehicle received via the transmitting/receiving means, thetime information for either the measurement time or the transmissiontime, and the position information for its own vehicle.

[0038] According to the third invention, in the vehicle interferenceprevention device of the first invention or the second invention,

[0039] the estimating means comprises:

[0040] first estimating means for estimating, on the basis of theposition information and the time information for other vehicle receivedvia the communication means, a future position of the other vehicle at apoint in time coming a predetermined time interval after the time, or arange of movement of the other vehicle;

[0041] second estimating means for estimating from its current positionon the basis of position information for its own vehicle a futureposition of its own vehicle at a point in time coming a predeterminedtime interval later, or a range of movement of its own vehicle; and

[0042] decision means for deciding if the future position or range ofmovement of the other vehicle estimated by the first estimating meansoverlaps the current position or future position of its own vehicleestimated by the second estimating means.

[0043] According to the fourth invention, in the device of firstinvention, second invention, or third invention, each of the pluralityof vehicles further comprises processing means that, during power-on ofits own vehicle, notifies other vehicle that its own vehicle has startedup, and in the event that no response to the notification is received byits own communication means, makes a determination that thecommunication means of the other vehicle is not functioning normally,and places its own vehicle in standby mode at its current position.

[0044] The first through third invention are now described makingreference to FIGS. 6, 7, 11, and 12.

[0045] To prevent interference among vehicles, the range of possiblelocations for other manned vehicles can be calculated by an unmannedvehicle or manned vehicle in the following manner, for example.

[0046] Method 1: Circle Computation Method

[0047] Referring to FIG. 6, an own vehicle (either an unmanned vehicleor a manned vehicle), for example, unmanned vehicle 10, uses thelast-acquired position data P (position at a certain point in time) fora manned vehicle (other vehicle) for example, manned vehicle 11),acquired (received) via inter-vehicle communication device 6 as thebasis for computing a circle 70 having position P as its center andhaving a radius r equal to the distance traveled at maximum speed frompoint P to a predetermined future point in time, and designates the areawithin this circle 70 on prearranged travel route 60 as range ofpossible locations for manned vehicle 11.

[0048] Method 2: Course Computation Method

[0049] Referring to FIG. 7, an own vehicle (either an unmanned vehicleor a manned vehicle), for example, unmanned vehicle 10, uses thelast-acquired position data P (position at a certain point in time) anddirection information (direction of progress indicated in the figure by□) for a manned vehicle acquired (received) via inter-vehiclecommunication device 6 as the basis for computing positions on anprearranged travel route 60 course), for example, position 60 a andposition 60 b on prearranged travel route 60—assuming movement of themanned vehicle at maximum speed from point P to a predetermined fixturepoint in time—and designates the area between point P and positions 60a, 60 b (crosshatched area in the figure) 71 as the range of possiblelocations for the manned vehicle.

[0050] The own vehicle respectively computes, for example,5-second-ahead and 15-second-ahead ranges of possible locations foritself and for the other vehicle, and determines for each of thesewhether these range of possible locations interfere with each other. Inthe event that the 15-second-ahead range of possible locationsinterfere, the vehicle (unmanned vehicle 10, for example) makes adetermination as to whether the reception time of position data for theother vehicle is older than predetermined time interval (30 seconds ormore, for example) (STEP 304 in FIG. 11), and where this predeterminedtime interval (30 seconds, for example) has already passed, the vehicleat risk for interference is requested directly for position informationby UHF transmission via the inter-vehicle communication device 6 (STEP305 in FIG. 11)

[0051] On the other hand, in the event that the 5-second-ahead range ofpossible locations interfere, travel of the vehicle (unmanned vehicle10, for example) is controlled by a vehicle control device 44 so as tostop as quickly as possible (STEP 406).

[0052] According to the first to third inventions described above, avehicle, on the basis of position information for itself, positioninformation transmitted to it from another vehicle, and time information(either the reception time, position measurement time, or transmissiontime for this position information), estimates the likelihood ofinterference between itself and another vehicle, and performsappropriate control on the basis of this estimate so as to avoidinterference between the vehicles.

[0053] Specifically, from the current position of other vehicle, anestimate is made of a range of movement for the other vehicle at a pointin time having passed a predetermined time interval form the time basedon the time information, thus allowing a determination to be made as towhether the estimated range of movement of the other vehicle interfereswith its own vehicle, the time interval between transmissions ofposition data over long distances can be increased, thereby reducing theload on the communications circuit.

[0054] The fourth invention is now described making reference to FIG. 9.

[0055] At power-on, a vehicle controller 55 provided to manned vehicle11 enters a malfunction detection mode, at which time a Power-on signaland Vehicle ID for manned vehicle 11 are transmitted to a monitoringstation 20 through UHF transmission via a monitoring station/vehiclecommunication device 5 (S11). Through UHF transmission via a monitoringstation/vehicle communication device 23, monitoring station 20 transmitsto all vehicles powered-up at that time (unmanned vehicles 10 and 12 inthis example) the Vehicle ID for the newly powered-up manned vehicle 11and a signal indicating that “manned vehicle 11 has powered up” (S12).In the event that an acknowledging signal is received, for example, fromunmanned vehicle 12 (S13) whereas no acknowledging signal is receivedfrom unmanned vehicle 10 after a predetermined time interval TA haspassed, Warning information is transmitted to manned vehicle 11 (S14),and the same signal (namely, the same signal as in S12) isre-transmitted to both unmanned vehicles 10 and 12 or to the vehiclefailing to respond, here, unmanned vehicle 10 (S15).

[0056] When manned vehicle 11 receives Warning information, itrecognizes that the vehicle communication devices 5, 6 of some or all ofthe other vehicles currently in operation (traveling) are notfunctioning normally, and goes into standby at its current position.

[0057] According to the fourth invention, the processing means of avehicle that has powered up transmits to other vehicles identifyinginformation that identifies its own vehicle and notification that itsown vehicle has powered up, and in the event that no response isreceived, recognizes that there is a malfunction with the communicationsmeans of the other vehicle or vehicles, and places its own vehicle instandby mode at its current position. In this way, the powered-up ownvehicle will commence travel only after verifying that it is safe to doso, so as to avoid colliding or otherwise interfering with othervehicles.

[0058] According to the fifth invention, there is provided a vehicleinterference prevention device having an unmanned vehicle comprisingvehicle position-measuring means for measuring a position of its ownvehicle and traveling over a travel route based on predeterminedinstruction data, a first manned vehicle having position-measuring meansfor measuring a position of its own vehicle, and a second manned vehicletraveling over the travel route guided by the first manned vehicle;

[0059] wherein the unmanned vehicle and the first manned vehicle eachcomprises communication means for transmitting and receivingpredetermined information among themselves;

[0060] the first manned vehicle transmits to the unmanned vehicle viathe communication means a mode which is either a guiding mode whereinthe second manned vehicle is guided, or a non-guiding mode wherein thesecond manned vehicle is not guided; and transmits to the unmannedvehicle via the communication means position information indicating thevehicle position determined by the position-measuring means; and

[0061] the unmanned vehicle, in the event that the mode received via thecommunication means is the non-guiding mode, is controlled, on the basisof the position information from the first manned vehicle, in such a wayas to avoid entering an area of a given range that includes a currentposition of the first manned vehicle; whereas in the case of the guidingmode, it is controlled, on the basis of the position information fromthe first manned vehicle, in such a way as to avoid entering the currentposition of the first manned vehicle and an area of a given range lyingto a rear of the first manned vehicle.

[0062] According to the sixth invention, the vehicle interferenceprevention device of the fifth invention,

[0063] further comprises a monitoring station havingtransmitting/receiving means for transmitting and receivingpredetermined information to and from the unmanned vehicle and the firstmanned vehicle; and

[0064] the monitoring station further comprises means for transmittingto the unmanned vehicle via the transmitting/receiving means instructiondata designating as a permissible travel range over which travel ispermitted an area on the travel route such that the most recent positionof the unmanned vehicle, based on the position information measured bythe vehicle position-measuring means and received via thetransmitting/receiving means, does not interfere with a predicted rangeof motion for the first manned vehicle, as calculated on the basis ofthe most recent position information for the first manned vehiclereceived via the transmitting/receiving means.

[0065] According to the seventh invention, in the vehicle interferenceprevention device of the sixth invention, the transmitting means, in theevent that the first manned vehicle is currently in the guiding mode,excludes from the permissible travel range a predicted range for thesecond manned vehicle that is obtained on the basis of the positioninformation for the second manned vehicle based on the positioninformation for the first manned vehicle, and transmits to the unmannedvehicle instruction data designating an area of this range as a newpermissible travel range.

[0066] According to the eighth invention, in the vehicle interferenceprevention device of the fifth invention, the unmanned vehiclecomprises:

[0067] measuring means for measuring the position of its own vehicle;

[0068] decision means for deciding, on the basis of the positioninformation from the first manned vehicle received from thecommunication means and position information indicating the position ofits own vehicle as measured by the measuring means, whether its ownvehicle poses interference with the first manned vehicle or with an areaof a predetermined range extending from the position of the mannedvehicle; and

[0069] control means that, in the event that the decision means decidesthat interference is present, halts or decelerates its own vehicle.

[0070] The fifth through eighth inventions are now described makingreference to FIGS. 16 and 17.

[0071] Let it be assumed that the vehicle computing a vehicle range ofpossible locations is an unmanned vehicle (unmanned vehicle 10, forexample; in actual practice, it does not matter if the vehicle is amanned vehicle or unmanned vehicle), and that the other vehicle whoserange of possible locations is being computed is a manned vehicle{escort vehicle (manned vehicle 11, for example) only, or an escortvehicle plus an escorted vehicle (such as a repair vehicle)}.

[0072] Methods for calculating a range of possible locations for avehicle include the following two, for example.

[0073] Method 1: Circle Computation Method

[0074] Referring to FIG. 16, on the basis of position data indicatingthe last reported vehicle position P (latest position data), unmannedvehicle 10 designates as a range of possible locations for escortvehicle 11 a circle 80 of radius r equivalent to the distance over whichthe latter vehicle can travel at maximum speed from vehicle position P.

[0075] The range of possible locations for the escorted vehicle consistsof an area defined by circle 80 and circles 81, 82 of radii equal to thedistances traveled at maximum speed from a point P1, lying within apredetermined distance from position P—which represents the lastreported vehicle position for which information has been received fromescort vehicle 11—defined as the escort area, and another point P2,respectively.

[0076] Method 2: Course Computation Method

[0077] Referring to FIG. 17, on the basis of position data indicatingthe last reported vehicle position P (latest position data) received viathe inter-vehicle communication device 6, unmanned vehicle 10 computespositions 60 a, 60 b on prearranged travel route 60 assuming movement ofthe manned vehicle at maximum speed along the prearranged travel routeup to a predetermined future point in time, and designates as the rangeof possible locations for the escort vehicle the area 90 on theprearranged travel route lying between these positions 60 a, 60 b andthe last reported vehicle position P

[0078] The range of possible locations for the escorted vehicle isdetermined by computing positions on the travel route assuming travel atmaximum speed from a point P1—lying within a predetermined distance 11defined as the escort area from position P which represents the lastreported vehicle position for which information has been received fromescort vehicle, and another point P2, respectively, and adding these toarea 90, previously computed on the basis of point P.

[0079] Unmanned vehicle 10, which computes a range of possible locationsfor the manned vehicle in the preceding manner, is provided bymonitoring station 20 with the Vehicle ID and mode information for themanned vehicle, as well as instruction data reflecting this modeinformation. Unmanned vehicle 10 is controlled by monitoring station 20so as to prevent it from entering the range of possible locations forthe manned vehicle.

[0080] Specifically, where the escort vehicle (manned vehicle 11) is innon-escort mode, unmanned vehicle 10 is controlled so as to prevent itfrom entering range of possible locations 80 computed using Method 1, orrange of possible locations 90 computed using Method 2; whereas inescort mode, it is controlled so as to prevent it from entering range ofpossible locations 80 and range of possible locations 81, 82 computedusing Method 1, or range of possible locations 90 and range of possiblelocations 91 computed using Method 2.

[0081] As will be apparent from the preceding description, according tothe fifth through eighth inventions, a second manned vehicle lackingposition-measuring means for measuring the position of its own vehicleand communication means for transmitting to an unmanned vehicle positiondata indicating the vehicle position determined thereby is guided by afirst manned vehicle equipped with position-measuring means andcommunication means, whereby the manned vehicle lackingposition-measuring means and communication means may be conducted safelyabout a large work site such as a mining operation.

[0082] In the event that the position-measuring means and communicationmeans of a first manned vehicle should fail to function properly due tomalfunction or the like, the first manned vehicle may nevertheless beconducted safely about a large work site guided by another first mannedvehicle.

[0083] According to the ninth invention, there is provided a vehicleinterference prevention device for preventing interference among aplurality of vehicles, including at least one manned vehicle, as theytravel along a travel route, wherein each of the plurality of vehiclescomprises:

[0084] measuring means for measuring a position of its own vehicle; and

[0085] communication means for exchanging with other vehicles positioninformation indicating the vehicle position measured by the measuringmeans;

[0086] and the manned vehicle comprises:

[0087] processing means for calculating relative positional relationshipof its own vehicle and other vehicle on the basis of positioninformation for the other vehicle received via the communication means,and position information for its own vehicle; and

[0088] notifying means for notifying predetermined information dependingon the relative positional relationship calculated by the processingmeans.

[0089] According to the tenth invention, in the vehicle interferenceprevention device of the ninth invention, wherein the notifying meanscomprises display means for visually displaying the relative positionalrelationship.

[0090] According to the eleventh invention, in the vehicle interferenceprevention device of the ninth invention or tenth invention, thenotifying means provides a warning in the event that the relativepositional relationship is such that its own vehicle and the othervehicle are in close proximity and interfering.

[0091] According to the twelfth invention, in the vehicle interferenceprevention device of the ninth invention, the plurality of vehiclesfurther comprises:

[0092] transmitting/receiving means for exchanging with other vehicletime information indicating either of a time at which the vehicleposition was measured by the measuring means of its own vehicle, or atime at which position information indicating this vehicle position wastransmitted; and

[0093] all of the manned vehicles including at least one manned vehiclefurther comprise:

[0094] range estimating means for estimating, on the basis of positioninformation for other vehicle received via its own communication means,and either time information for this position information indicating thetime at which the position information was received by the communicationmeans, or the time information having been transmitted by the othervehicle, a range of movement of other vehicle from a position based onthe position information to another position at a point in time comingafter a predetermined time interval has passed; and

[0095] display means for displaying the relative positional relationshipcalculated by the processing means, and for displaying the range ofmovement estimated by the range estimating means for the other vehiclein the positional relationship.

[0096] The ninth through twelfth inventions are now described makingreference to FIGS. 6, 7, and 16-19.

[0097] The manned vehicle displays on the display screen of its displaydevice 52 a information pertaining to the range of possible locationsfor another manned vehicle or unmanned vehicle, as depicted in FIGS. 16and 17, for example. Where the other vehicle is a manned vehicle, and itis further the case that the range of possible locations for the ownvehicle and the range of possible locations for the other vehicleinterfere, with the other vehicle expected to travel in the samedirection over the prearranged travel route for the vehicle, there isissued Warning information to the effect that there is a risk ofovertaking the other vehicle (STEP 706 in FIG. 18), whereas if the othervehicle is not traveling in the same direction, there is issued Alarminformation warning of the risk of collision with the other vehicle(STEP 707 in FIG. 18).

[0098] Substantially identical processes are performed where the othervehicle is an unmanned vehicle (STEP 806, STEP 807 in FIG. 19).

[0099] Specific examples of the above-mentioned Warning informationwould be, for example, a display on the display screen of display device52 a to the effect that there is a risk of overtaking the other vehicle,or lighting up of the yellow light of indicator light 52 b. Acombination of the above is also possible. Specific examples of theabove-mentioned Alarm information would be, for example, a display onthe display screen of display device 52 a to effect that there is a riskof collision with the other vehicle, for example; lighting up of the redlight of indicator light 52 b; or a buzzer sound emitted by an alarmbuzzer 52 c. Combinations of the above are also possible.

[0100] As noted, according to the ninth through eleventh inventions, amanned vehicle is informed of the relative positional relationship ofitself and another vehicle, allowing the human operator of the mannedvehicle (own vehicle) to ascertain before the fact the likelihood that,on the current course, the vehicles will interfere, for example, so thatinterference between the vehicles can be avoided.

[0101] In particular, visual display of the relative positionalrelationship of the own vehicle and the other vehicle on a display meansaffords better recognition of the relative positional relationship.

[0102] In the event of impending interference between vehicles, awarning to this effect is provided so that interference between thevehicles can be avoided.

[0103] According to the twelfth invention, the relative positionalrelationship of an own vehicle and other vehicle, as well as the rangeof movement of the other vehicle with which this positional relationshipexists, are displayed by display means, allowing the operator to verifycurrent and future positional relationships vis-á-vis the other vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

[0104]FIG. 1 is a diagram showing the exterior aspect of an entiremonitoring vehicle system representing an embodiment of the vehicleinterference prevention device which pertains to the invention;

[0105]FIG. 2 is a block diagram showing the communication systemarrangement in the embodiment;

[0106]FIG. 3 is a block diagram showing device arrangement on-board anunmanned vehicle;

[0107]FIG. 4 is a block diagram showing device arrangement on-board amanned vehicle;

[0108] FIGS. 5(a) and 5(b) are diagrams of an exemplary screen displaydisplayed on the display device of a manned vehicle;

[0109]FIG. 6 is a diagram illustrating range of possible locations for avehicle (manned vehicle);

[0110]FIG. 7 is a diagram illustrating range of possible locations for avehicle (manned vehicle);

[0111]FIG. 8 is a flow chart of a process operation by a monitoringstation during power-on of a manned vehicle;

[0112]FIG. 9 is a sequence diagram showing a process operation by avehicle monitoring system during power-on of a manned vehicle;

[0113]FIG. 10 is a flow chart showing a process operation by an unmannedvehicle;

[0114]FIG. 11 is a flow chart showing an interference estimation processoperation by a vehicle;

[0115]FIG. 12 is a flow chart showing an interference estimation processoperation by a vehicle;

[0116] FIGS. 13(a) to 13(c) are diagrams illustrating a range ofpossible locations for a vehicle;

[0117]FIG. 14 is a flow chart showing a process operation by SStransmission;

[0118]FIG. 15 is a flow chart showing a process operation by SStransmission;

[0119]FIG. 16 is a diagram illustrating a range of possible locationsfor a vehicle (manned vehicle) in a second embodiment;

[0120]FIG. 17 is a diagram illustrating a range of possible locationsfor a vehicle (manned vehicle) in a second embodiment;

[0121]FIG. 18 is a flow chart showing a process operation by SStransmission in a third embodiment; and

[0122]FIG. 19 is a flow chart showing a process operation by SStransmission in a third embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0123] The embodiments of the vehicle interference prevention devicepertaining to the invention are described hereinbelow making referenceto the accompanying drawings.

[0124]FIG. 1 depicts the exterior aspect of an entire vehicle monitoringsystem for managing and monitoring a multitude of dump trucks 10, 11,12, 13 in a large work site 30 such as a mine.

[0125]FIG. 2 is a block diagram showing only the communication systemfor the vehicle monitoring system.

[0126] Referring to FIG. 1, the vehicle monitoring system broadlycomprises a plurality of dump trucks (hereinafter termed simply“vehicles”) 10, 11, 12, 13, each comprising vehicle position-measuringmeans, described later, for measuring the position (X, Y) of its ownvehicle, and a monitoring station 20 for receiving the position data (X,Y) transmitted by each of the plurality of vehicles, and for using thereceived position data as the basis for monitoring positionalrelationships among the plurality of vehicles while transmittinginstruction data instructing the plurality of vehicles to move, stop,etc.

[0127] The present embodiment presumes that both unmanned vehicles andmanned vehicles are present; here, vehicles 10 and 12 are unmannedvehicles, whereas vehicles 11 and 13 are manned vehicles.

[0128] While the present embodiment involves dump trucks as thevehicles, implementation with wheel loaders, hydraulic shovels, and thelike is also possible, as is implementation in systems in which dumptrucks, wheel loaders, hydraulic shovels, and the like are presenttogether.

[0129] In the case of hydraulic shovels, for example, interference canbe prevented by providing a plurality of GPS and rotation sensors to therotating boom of a piece of equipment so as to allow for mutualcommunication of vehicle orientation and status of the equipment.

[0130] As shown in FIG. 2, monitoring station 20 and the plurality ofvehicles are in wireless communication through monitoringstation/vehicle communication devices 23, 5.

[0131] Specifically, monitoring station/vehicle communication devices23, 5 that use a communications format, such as UHF, affording wirelesscommunication over the distances between the monitoring station 20 andthe plurality of vehicles, i.e., over the entirety of large work site30, are provided to the monitoring station 20 and to each of thevehicles 10, . . . , in order that position data and instruction datamay be transmitted and received among the monitoring station 20 and theplurality of vehicles.

[0132] The monitoring station/vehicle communication device 23 providedto monitoring station 20 comprises a transmitter 21 and a receiver 22,while the monitoring station/vehicle communication device 5 provided tovehicle 10 comprises a transmitter 1 and a receiver 2, with wirelesscommunication A taking place via an antenna 20 a of monitoring station20 and an antenna 10 a of vehicle 10, as shown in FIG. 1. For the othervehicles as well, wireless communication B takes place via the antenna20 a of monitoring station 20 and an antenna 11 a of vehicle 11,wireless communication C takes place via the antenna 20 a of monitoringstation 20 and an antenna 12 a of vehicle 12, and wireless communicationD takes place via the antenna 20 a of monitoring station 20 and anantenna 13 a of vehicle 13, respectively.

[0133] Monitoring station 20 further comprises a GPS (global positioningsystem) receiver (not shown) for receiving signals transmitted bysatellite. Monitoring station 20 computes position measurement error onthe basis of accurate data indicating its own position as a referencepoint and position data from measurements by the GPS receiver, andtransmits to each vehicle via transmitter 21 and antenna 20 a correctiondata (differential data) for eliminating the position measurement error.

[0134] Control on the basis of communications between the monitoringstation/vehicle communication devices does not pertain directly to thegist of the invention and for this reason a detailed discussion is notprovided here.

[0135] The plurality of vehicles, on the other hand, are in wirelesscommunication through inter-vehicle communication devices 6.

[0136] Specifically, inter-vehicle communication devices 6 using acommunications format, such as SS (spread spectrum) transmission, thataffords wireless communication over the distances among the plurality ofvehicles at faster data transmission speeds than the aforementionedmonitoring station/vehicle communication devices 23, 5 are provided toeach of vehicles 10 to 13, so that data of various kinds, such as theaforementioned position data or control instruction data (describedlater) can be exchanged among the plurality of vehicles.

[0137] The inter-vehicle communication device 6 of each vehiclecomprises a transmitter 3 and a receiver 4; as shown in FIG. 1, wirelesscommunication E is carried out via antenna 10 b of vehicle 10 andantenna 11 b of vehicle 11, wireless communication F is carried out viaantenna 11 b of vehicle 11 and antenna 12 b of vehicle 12, wirelesscommunication G is carried out via antenna 10 b of vehicle 10 andantenna 12 b of vehicle 12, wireless communication H is carried out viaantenna 10 b of vehicle 10 and antenna 13 b of vehicle 13, and wirelesscommunication I is carried out via antenna 12 b of vehicle 12 andantenna 13 b of vehicle 13, respectively. Wireless communicationoccasionally becomes impossible where the distance between vehicles(vehicle 11 and 13, for example) exceeds the distance over which radiowaves can travel.

[0138] To prevent interference between vehicles, each vehicleperiodically broadcasts identification information identifying itself(hereinbelow termed “Vehicle ID”) and current position data indicatingthe current position of itself to all other vehicles and to themonitoring station through UHF transmission, while also periodicallybroadcasting its own Vehicle ID and current position data to proximatevehicles by SS transmission.

[0139] Broadcasting refers to communications requiring no acknowledgmentfrom the receiving wireless station (a vehicle, for example). Sincesimultaneous communication with all wireless stations without any needfor acknowledgement is possible, wireless resources can be usedeffectively.

[0140] When position data for an own vehicle is broadcast to othervehicle, transmitter 3 recognizes, by means of timing means such as atimer, the point in time at which it transmits this position data, andcan transmit this transmission time information.

[0141] When position data is transmitted (broadcast) to receiver 4 fromanother vehicle, it can recognize, by means of timing means such as atimer, the point in time at which position data is received, and canstore this reception time information.

[0142] This transmission time information or reception time informationconstitutes reference time information needed to estimate, on the basisof the current vehicle position, a position after a predetermined timeinterval has elapsed. Through a pre-established process it is possibleto have the vehicle monitoring system use one or the other of this timeinformation. Specifically, where reception time information is to beused on a system-wide basis, the transmission time information transmitfunction of transmitter 3 is halted and the reception time informationhold function of receiver 4 is used, whereas if transmission timeinformation is to be used, the transmission time information transmitfunction of transmitter 3 is used and the reception time informationhold function of receiver 4 is halted. The present embodiment describesa scenario in which reception time information is used.

[0143] The reason for employing UHF transmission for long-distancecommunications and SS transmission for short-distance communications isthat UHF transmission, while having small communications capacity (about9600 bps), can transmit over long distances (10 km-20 km) and as suchcan cover the entire mine site (entire large work site) either directlyor with the aid of one or two repeaters (relays), whereas SStransmission, while limited to short distances (100 m-1 km) has a largecommunications capacity (256 Kbps) and is thus suited to frequentexchanges of information among vehicles.

[0144]FIG. 3 is a block diagram showing device arrangement on-boardunmanned vehicles (unmanned dump trucks) 10, 12.

[0145] Referring to FIG. 3, each unmanned vehicle comprises aposition-measuring device 41, built around a CPU (central processingunit), for determining the current position of its own vehicle (vehicle10, for example); the communication devices 5 and 6 described earlier; acourse storage device 42 for storing course data indicating anprearranged travel route, and the like; a data storage device 43 forstoring data received via communication device 6; and a vehicle controlunit 44 for drive control of its own vehicle 10.

[0146] Position-measuring device 41 comprises a D (differential)-GPS(global positioning system) 41 a for determining the current position ofits own vehicle through signals received from satellites, and an INS(inertial navigation system) 41 b for determining the speed of its ownvehicle; these measurements are output to the vehicle control unit 44.

[0147] In addition to calculating current position, position-measuringdevice 41 also compares preset course data to actual measured positiondata to determine direction of progress, accuracy of positionmeasurement, deviation from course (prearranged travel route), andangular deviation from the stipulated direction on the prearrangedtravel route.

[0148] D-GPS 41 a calculates an accurate current position by correctingthe measured vehicle current position on the basis of differential datatransmitted by monitoring station 20.

[0149] Course storage device 42 stores data indicating a prearrangedtravel route, obtained by teaching a prearranged travel route prior tothe actual work.

[0150] Monitoring station 20 transmits, via transmitter 21 of monitoringstation/vehicle communication device 23, instruction data indicating afinal target point (destination) for each vehicle to initiate playbackoperation.

[0151] Data storage device 43 stores position data—received viacommunication device 6—indicating the positions of other vehicles; andtime information selected from reception time information for positiondata of the other vehicle received by its communication device 6,measurement time information indicating the time at which the vehicleposition transmitted by the other vehicle was measured, and transmissiontime information for transmission of position data for the vehicle.

[0152] Vehicle control unit 44 controls steering angle, braking,transmission, and engine speed on the basis of data indicating currentspeed and current position of vehicle 10 measured byposition-measurement device 41; instruction data (instructions to halt,decelerate, etc.) received from monitoring station 20 via monitoringstation/vehicle communication device 5; and course data stored in coursedata storage device 42.

[0153] Specifically, a target engine speed is set, and the fuelinjection rate is controlled in response to an electrical signal appliedto an electronic control governor in order to change engine speed.Actual engine speed is sensed by an engine speed sensor, the signal fromthe sensor serving as a feedback signal for controlling engine speed.

[0154] Where the forward/reverse clutch is in forward or reverse (i.e.,not in neutral), engine power is transmitted to the tires via a torqueconverter, transmission, propeller shaft, and differential gear, wherebychanges in engine speed produce changes in the travel speed of vehicle10.

[0155] A hydraulic pump is driven by the engine, and the hydraulic fluidfrom this hydraulic pump is delivered to a hydraulic actuator thatactuates a load-carrying platform or the like, and is at the same timedelivered via a steering hydraulic electromagnetic proportional valve toa steering cylinder that actuates the steering, whereby steering isactuated in response to an electrical signal presented to the steeringhydraulic electromagnetic proportional valve to change the steeringangle.

[0156] A target value for braking pressure is established, and brakingpressure is changed in response to an electrical signal presented to abraking pneumatic electromagnetic proportional valve to operate thebrakes. The brakes are provided with brake pressure sensors for sensingbrake pressure, the signals from the sensors serving as a feedbacksignals for controlling braking pressure.

[0157]FIG. 4 is a block diagram showing device arrangement on-boardmanned vehicles (manned dump trucks) 11, 13.

[0158] Referring to FIG. 4, the manned vehicle (manned vehicle 11, forexample) is built around a CPU (central processing unit) and comprisesthe aforementioned communication devices 5, 6; a position-measurementdevice 51 analogous in function to position-measurement device 41described previously; a status indicator device 52; an other vehiclecontrol portion 53 for stopping another unmanned vehicle; a backup powersupply 54; and a vehicle controller 55.

[0159] Status indicator device 52 comprises a display device 52 a forgraphical display of the position of its own vehicle and other vehicleson a predetermined travel route (course) in the mine; an indicator light52 b for indicating by three colored indicator lights whether or nottravel is permitted; and an alarm buzzer 52 c for indicating vehiclemalfunction.

[0160] By operating predetermined switches on the console, displaydevice 52 a can display an enlarged view (FIG. 5(a)) or a reduced view(FIG. 5(b)) of a prearranged travel route 60 in the mine and therelative positional relationship of the position of the other vehicle(unmanned vehicle 10, for example) and the position of its own vehicle(manned vehicle 11, for example).

[0161] Display device 52 a also displays vehicle target position andcourse to be traveled (prearranged travel route) instructions, haltinstructions, deceleration instructions, and other instruction datatransmitted from monitoring station 20.

[0162] Indicator light 52 b comprises three indicator lights (lamps),blue, yellow, and red. When lit, the indicator lights indicate thefollowing.

[0163] Blue: No other vehicle present ahead of vehicle (travelpermitted)

[0164] Yellow: Caution: unmanned vehicle nearby

[0165] Red: Stop: unmanned vehicle approaching (travel not permitted)

[0166] Extinguishing of all three indicator lamps also indicates thattravel is not permitted.

[0167] Accordingly, the human operator must manually control the vehiclein response to instruction data displayed on display device 52 a and thestatus of indicator lights 52 b. Of course, the alarm buzzer 52 cindicates a risk of collision with another vehicle and requires that thevehicle be halted quickly.

[0168] The emergency stop button 53 a of other vehicle control portion53 is used, by depressing the button 53 a in the event of a risk ofcollision of its own vehicle with another vehicle or the like, totransmit, instruction data for halting the unmanned vehicle to theunmanned vehicle via vehicle controller 55 and communication device 6.Emergency stop button 53 a is also used to reset indicator light 52 bwhen all three indicator lights are lit, and to reset alarm buzzer 52 cwhen the buzzer sounds.

[0169] Backup power supply 54 provides backup for communication devices5, 6 and vehicle controller 55 in the event that travel is terminatedand power is shut off. This allows notification that power has been shutoff and position data indicating the position of the stopped vehicle tobe transmitted to monitoring station 20 via monitoring station/vehiclecommunication device 5 under the control of vehicle controller 55.

[0170] While vehicle controller 55 functions analogously to vehiclecontrolled device 44, steering angle, braking, transmission, and enginespeed are basically controlled manually by a human operator, but brakingand engine speed are controlled automatically in some instances.

[0171] Specifically, the human operator operates the console inaccordance with instructions from monitoring station 20 displayed ondisplay device 52 a in order to manually control steering angle,braking, transmission, and engine speed.

[0172] However, in the event that instructions stipulated in instructiondata displayed on display device 52 a are not performed by the time apredetermined time interval has passed, braking and engine speed arecontrolled automatically so that the instruction data is followedautomatically in order to decelerate or stop the manned vehicleautomatically.

[0173] Vehicle controller 55 comprises a storage area 55 a for storingdata received via communication devices 5, 6. Storage area 55 a stores,for example, position data received via inter-vehicle communicationdevice 6 and indicating the positions of other vehicles; and timeinformation selected from reception time information for position datafor other vehicle received by its inter-vehicle communication device 6,measurement time information indicating the time at which the vehicleposition transmitted by the other vehicle was measured, and transmissiontime information indicating the time at which the position data for thevehicle was transmitted.

[0174] Methods for estimating a range of possible locations for anotherunmanned vehicle by an unmanned vehicle or a manned vehicle in order toprevent interference among, vehicles are now described. Two such methodsare as follows.

[0175] Method 1: Circle Computation Method

[0176] Referring to FIG. 6, the own vehicle (either an unmanned vehicleor a manned vehicle), for example, unmanned vehicle 10, uses the lastposition P (position at a certain point in time) based on the positiondata for a manned vehicle (other vehicle) for example, manned vehicle11) acquired (received) via inter-vehicle communication device 6 as thebasis for computing a circle 70 having position P as its center andhaving a radius r, this radius being equal to the distance traveled atmaximum speed from point P to a predetermined future point in time, andestimates an area within this circle 70 on prearranged travel route 60as a range of possible locations (a range of movement) for mannedvehicle 11.

[0177] Method 2: Course Computation Method

[0178] Referring to FIG. 7, an own vehicle (either an unmanned vehicleor a manned vehicle), for example, unmanned vehicle 10, uses thelast-acquired position data P (position at a certain point in time) anddirection information (direction of progress indicated in the figure by□) for a manned vehicle acquired (received) via inter-vehiclecommunication device 6 as the basis for computing positions on aprearranged travel route 60 (course), for example, position 60 a andposition 60 b on prearranged travel route 60—assuming movement of themanned vehicle at maximum speed from point P to a predetermined futurepoint in time—and designates the area between point P and positions 60a, 60 b (crosshatched area in the figure) 71 as the range of possiblelocations for the manned vehicle.

[0179] In the example depicted in FIG. 7, prearranged travel route 60forks midway, which means that the estimated range over which mannedvehicle 11 can travel a given distance from position P is the distanceextending to position 60 a and the distance extending to position 60 b.

[0180] A range of possible locations for the manned vehicle can also beestimated using a combination of the two methods. For example, Method 1can be used for long distances and Method 2 used for shorter distances.Alternatively, rather than plotting a circular range of possiblelocations using Method 1, one may plot an ellipse having greaterextension in the direction of forward advance of the vehicle from theposition of the other vehicle. That is, one may plot an ellipse havingthe direction of forward advance of the vehicle as its major axis.

[0181] When using the circle computation of Method 1, there exists arisk that the estimated future range of possible locations for the othervehicle may interfere with the own vehicle if the distance between thetwo vehicles has been shortened by passing by each other, for example.This may be avoided by employing Method 2; or by employing Method 1 forlong distances, while for shorter distances transmitting to the othervehicle, by means of SS transmission, direction of advance informationand predicted route information in addition to position information, soas to provide a more precise estimate of range of possible locations.

[0182] The preceding discussion relates to computing a range of possiblelocations for a manned vehicle, but these same methods may be utilizedin computing a range of possible locations for an unmanned vehicle.

[0183] According to the present embodiment, data can be exchanged asfollows between vehicles situated in close proximity to each other suchthat SS transmission is possible.

[0184] An unmanned vehicle transmits to another vehicle position dataindicating its current vehicle position and position data at a pluralityof points on a predetermined travel course. At the same time, dataindicating the current position measurement accuracy and data indicatingpositional deviation are transmitted to other vehicles.

[0185] A manned vehicle, meanwhile, transmits to another vehicleposition data indicating its current vehicle position and informationconcerning the direction of advance. At the same time, data indicatingthe current position measurement accuracy, data indicating positionaldeviation from the course, and data indicating angular deviation from anindicated direction on the course are transmitted to other vehicles.

[0186] At this time, in the event that positional deviation and angulardeviation of the manned vehicle should exceed stipulated values, theunmanned vehicle will halt the own vehicle and transmit an alarm signalto this other vehicle (manned vehicle).

[0187] Between vehicles that are close enough together thatcommunication via SS transmission is possible, the range of possiblelocations of the other vehicle or own vehicle is estimated as follows.

[0188] For an unmanned vehicle, the range of possible locations isestimated as a path connecting a plurality of points on a prearrangedtravel route, of width including latitude for position measurementaccuracy, positional deviation, and vehicle width.

[0189] For a manned vehicle, on the other hand, the range of possiblelocations is estimated as a circle centered on the current position, ofdiameter including latitude for position measurement accuracy andvehicle width.

[0190] Broadly speaking, this vehicle monitoring system can take eitherof two patterns, one in which the own vehicle is an unmanned vehicle,and the other vehicle is either a manned vehicle or unmanned vehicle,with data being exchanged between these vehicles; and one in which theown vehicle is a manned vehicle, and the other vehicle is either amanned vehicle or unmanned vehicle, with data being exchanged betweenthese vehicles.

[0191] The present embodiment assumes the first pattern (namely, thatthe own vehicle is an unmanned vehicle and the other vehicle is either amanned vehicle or unmanned vehicle). A description of the specifics ofthe process for preventing interference between vehicles follows.

[0192] Processing by monitoring station 20 during power-on (turning onthe power supply) of the manned vehicle in a vehicle monitoring systemof this design is now described making reference to the flow chart ofFIG. 8.

[0193] Referring to FIG. 8, upon receiving via monitoringstation/vehicle communication device 23 a signal from the manned vehicleto the effect that “power has been turned on” and the Vehicle ID (STEP101), monitoring station 20 broadcasts via monitoring station/vehiclecommunication device 23 a signal to the effect that “the manned vehiclepower has been turned on” and the vehicle ID of the manned vehicle (STEP102), while awaiting an acknowledging signal (ACK) from each vehicle(STEP 103), and determines if acknowledging signals have been receivedwithin a predetermined time interval from all vehicles operating at thattime (STEP 104).

[0194] If acknowledging signals are not received from all vehicles inSTEP 104, monitoring station 20 determines that some vehicles areunaware that the manned vehicle has been powered up, and issues Warninginformation to this effect, which is transmitted to the powered-upmanned vehicle via monitoring station/vehicle communication device 23(STEP 105), and then proceeds to STEP 102; on the other hand, ifacknowledging signals are received from all vehicles, it transmits tothe powered-up manned vehicle a signal to the effect that “the systemacknowledges the manned vehicle” via monitoring station/vehiclecommunication device 23 (STEP 106).

[0195] The manned vehicle, having received via monitoringstation/vehicle communication device 5 a signal to the effect that “thesystem acknowledges the manned vehicle,” can now be driven under controlof the human operator.

[0196] The preceding process is now described in detail making referenceto FIG. 9. FIG. 9 is a sequence diagram showing exchange of data amongthe monitoring station, vehicles in operation, and the manned vehiclebeing powered up.

[0197] Here, is it assumed that data is exchanged among the mannedvehicle 11 being powered up, an unmanned vehicle 10 in operation at adistance from manned vehicle 11 such that communication by SStransmission is possible, an unmanned vehicle 12 in operation at adistance from manned vehicle 11 such that communication by UHFtransmission is possible, and monitoring station 20, shown in FIG. 1.

[0198] At power-on, the vehicle controller 55 of manned vehicle 11enters malfunction detection mode, at which time a Power-on signal andVehicle ID for manned vehicle 11 are transmitted to monitoring station20 through UHF transmission via communication device 5 (S11).

[0199] Through UHF transmission via a monitoring station/vehiclecommunication device 23, monitoring station 20 transmits to all vehiclescurrently in operation (unmanned vehicles 10 and 12 in this example) theVehicle ID for the newly powered-up manned vehicle 11 and a signalindicating that “manned vehicle 11 has powered up” (S12), and awaits anacknowledging signal (ACK) from each vehicle. Let it be assumed here byway of example that an acknowledging signal has been received fromunmanned vehicle 12 (S13) whereas no acknowledging signal has beenreceived from unmanned vehicle 10 even after a predetermined timeinterval TA has passed; in this event, Warning information istransmitted to manned vehicle 11 (S14), and the same signal (namely, thesame signal as in S12) is re-transmitted to both unmanned vehicles 10and 12 or to unmanned vehicle 10 which has failed to respond (S15).

[0200] Where unmanned vehicle 10 responds with an acknowledging signal(S16) so that acknowledging signals have been input from all vehicles,monitoring station 20 transmits to manned vehicle 11 a signal to theeffect that “the system acknowledges the manned vehicle.”

[0201] If, after transmitting the signal, no answer is received despitepassage of an additional predetermined time interval, monitoring station20 issues an Abnormal Status message to manned vehicle 11.

[0202] Upon receiving an Abnormal Status message, manned vehicle 11recognizes that the communication devices 5, 6 of some or all of theother vehicles in operation (traveling) are malfunctioning, and goesinto standby at its current vehicle position.

[0203] Specifically, if, during power-on, manned vehicle 11 fails toreceive via monitoring station/vehicle communication device 5 a responsefrom monitoring station 20 (that is, from another vehicle currently inoperation (for example, unmanned vehicle 10 or 12 or manned vehicle 13))to notification of its own vehicle ID and notification that it haspowered up, manned vehicle 11 recognizes that the communication devices5, 6 of the other vehicle are malfunctioning and goes into standby atits current vehicle position.

[0204] Where manned vehicle 11 has received a signal indicating that“the system acknowledges the manned vehicle,” it recognizes that thecommunication devices 5, 6 of the other vehicles are functioningnormally.

[0205] The vehicle controller 55 of the manned vehicle 11—havingreceived a signal indicating that the system acknowledges the mannedvehicle—will, if no other abnormal states are detected, light all of theindicator lights of indicator light 52 b for a 10-second period, andsound the buzzer of alarm buzzer 52 c. The human operator (driver) mustdepress (depress a first time, for example) emergency stop button 53 ain order to turn off the indicator light lamps and the buzzer, and mustthen again depress emergency stop button 53 a (depress a second time,for example) in order to exit malfunction detection mode.

[0206] If vehicle controller 55 does not detect depression of emergencystop button 53 a after a predetermined time interval has elapsed, after10 seconds it displays a message to this effect on display device 52 aand lights up the red light of indicator light 52 b to notify the driverthat operation has been disabled. Malfunction of emergency stop button52 c will result in disabled operation. Alternatively, in such asituation the driver, having been notified of a malfunction by indicatorlight 52 b and the alarm buzzer, must stop operation of the vehicle.

[0207] Once operation has been enabled by twice depressing emergencystop button 53 a to exit malfunction detection mode, manned vehicle11—which is now enabled for travel—broadcasts current vehicle positiondata (the initial current position is the position at which it isstopped) and vehicle ID for manned vehicle 11 at periodic intervals TU(once about every 15 seconds, for example) by UHF transmission viainter-vehicle communication device 6 to the unmanned vehicles (allvehicles) 10, 12, as well as broadcasting this current vehicle positioninformation and vehicle ID to monitoring station 20 via monitoringstation/vehicle communication device 6 (S18, S21). It also broadcastscurrent vehicle position information and vehicle ID at periodicintervals TS (one about every 0.5 seconds, for example) by SStransmission via inter-vehicle communication device 6 to a proximatevehicle 10 (S19, S20).

[0208] In the example depicted in FIG. 9, for simplicity of description,the sequence chart shows broadcasting current position information bymanned vehicle 11 only, but in actual practice unmanned vehicles 10 and12, like manned vehicle 11, will also broadcast current position data.That is, all traveling vehicles broadcast their current position data toother vehicles or to monitoring station 20. While it is assumed herethat all traveling vehicles are unmanned vehicles, they could just aseasily be all manned vehicles, or a combination of manned vehicles andunmanned vehicles.

[0209] Unmanned vehicle operation is now described making reference toFIG. 10.

[0210] Referring to FIG. 10, an unmanned vehicle receives viainter-vehicle communication device 6 vehicle position data and a VehicleID transmitted to it from another vehicle (manned vehicle or unmannedvehicle) by SS transmission or UHF transmission (STEP 201), and afterupdating the position data (most recent position data) and measurementtime information for the other vehicle identified by this Vehicle ID(STEP 202), it executes a vehicle interference prevention process (STEP203).

[0211] The vehicle interference prevention process may be carried out byeither of two processes, described below.

[0212] First, the unmanned vehicle repeats the following process atgiven time intervals (100 msec, for example), as depicted in FIG. 11.

[0213] Specifically, on the basis of its current position, the unmannedvehicle calculates an estimated vehicle position for itself within agiven time interval (15 seconds, for example) (STEP 301), and for allother vehicles currently in operation (manned vehicles or unmannedvehicles) calculates for each, on the basis of the position representedin the last-reported current position information from the othervehicle, a range of possible locations after a given time interval (15seconds, for example) assuming movement of the vehicle at maximum speed(STEP 302).

[0214] Next, a decision is made as to whether the range of possiblelocations (ranges of movement) for another vehicles will interfere withthe range of possible locations (range of movement) for the own vehicle(STEP 303); where there is no interference, it proceeds to STEP 302.

[0215] Where interference appears in STEP 303, the unmanned vehiclemakes a decision as to whether the point in time at which it calculatedthe range of possible locations postdates, in excess of a predeterminedtime interval (30 seconds or more, for example), the point in time atwhich position data for the other vehicle was received (STEP 304). Ifthis predetermined time interval has not been exceeded, it proceeds toSTEP 302, whereas if this predetermined time interval has been exceeded,it makes a direct request for position data to the vehicle at risk forinterference (STEP 305) by UHF transmission via inter-vehiclecommunication device 6.

[0216] Vehicles at risk for interference are identified as follows.Since position data and vehicle IDs are broadcast from the othervehicles, where the point in time at which a range of possible locationsis calculated on the basis of position data exceeds this predeterminedtime interval, the vehicle ID paired with this position data can bereferenced to identify the vehicle. A request for position informationis made to the vehicle identified by this vehicle ID.

[0217] Next, the unmanned vehicle repeats the following process at giventime intervals (100 msec, for example), as depicted in FIG. 12.

[0218] On the basis of its current position, the unmanned vehiclecalculates an estimated vehicle position for itself within a given timeinterval (5 seconds, for example) (STEP 401), and for all other vehiclesrecognized as being currently in operation (manned vehicles or unmannedvehicles) decides whether communication with each by SS transmission ispossible (STEP 402).

[0219] Where SS transmission is determined to be possible, a controlprocess by SS transmission is initiated (STEP 403), whereas if SStransmission is determined to be impossible, a range of possiblelocations after a given time interval (5 seconds, for example)—assumingmovement of each vehicle at maximum speed—is computed on the basis ofthe position represented in the last-reported current positioninformation from the other vehicle (STEP 404).

[0220] Next, a decision is made as to whether the range of possiblelocations (ranges of movement) for another vehicles interferes with therange of possible locations (range of movement) for the own vehicle(STEP 405); where there is no interference, it proceeds to STEP 402,whereas if interference appears, the own vehicle (unmanned vehicle)performs travel control by means of vehicle control device 44 so as tostop at the maximum speed (STEP 406).

[0221] The particulars discussed in FIGS. 11 and 12 are described ingreater detail making reference to FIGS. 13(a) to 13(c).

[0222] Referring to FIG. 13(a), when position data for another vehicleis received by the own vehicle at time t1, this own vehicle calculatesat 100 msec intervals circles having as their radii the distances overwhich the own vehicle and the other vehicle can travel overpredetermined time intervals, namely, 5 seconds and 15 seconds, as shownin FIG. 13(b).

[0223] Specifically, the range of possible locations at time t1 for theother vehicle 5 seconds in the future is calculated as a circle S1having a radius r1 equal to 5 sec.×maximum speed v, and that for 15seconds in the future is calculated as a circle S2 having a radius R1equal to 15 sec.×maximum speed v. Circular ranges of possible locationsfor the own vehicle are calculated in the same manner on the basis ofcurrent traveling speed.

[0224] During the interval from time t1—at which the current positiondata was reported—to the next position data report coming 15 secondslater, a range of possible locations at time t2, coming after a timeinterval T—which is a positive integer multiple of 100 msec—iscalculated in the following manner. Referring to FIG. 13(c), for 5seconds in the future, a circle S1 having a radius r2 equal to (5sec.+T)×maximum speed v (the circle having as its center the position attime t1) is calculated, and for 15 seconds in the future, a circle S2having a radius R2 equal to (15 sec.+T)×maximum speed v (the circlehaving as its center the position at time t1) is calculated in the samemanner.

[0225] As regards range of possible locations for the own vehicle, sincevehicle position is constantly measured by the position-measuring device51 of the vehicle, its position at time t2 is known, whereby a circlehaving as its basis (the center of the circle) the position at time t2can be calculated on the basis of current travel speed, as shown in FIG.13(b).

[0226] When position data for the other vehicle is reported 15 secondslater, a range of possible locations for the other vehicle is calculatedas a circle having as its center this position, as shown in FIG. 13(b).The above process is subsequently repeated.

[0227] In the event that, owing to a malfunction of the inter-vehiclecommunication device 6 of the other vehicle or the like, position datacannot be received from the other vehicle, time interval T assumes alarge value at, for example, (5 sec.+T)×maximum speed v=r2 at 5 secondsin the future, so the range of possible locations for the other vehicleincreases in area (the circle becomes larger), as shown in FIG. 13(c).Thus, the range of possible locations for the other vehicle and therange of possible locations for the own vehicle will interfere, so theprocess of STEP 305 of FIG. 11 or of STEP 406 of FIG. 12 is performed.As a result, control is performed so as to prevent interference.

[0228] Next, the process of aforementioned STEP 403, namely, unmannedvehicle control by SS transmission, is described. Here, the othervehicle may be either a manned vehicle or an unmanned vehicle; the caseof a manned vehicle is described first, followed by a description of thecase of an unmanned vehicle.

[0229] Other Vehicle=Manned Vehicle

[0230] Referring to FIG. 14, an own vehicle (unmanned vehicle) receivesfrom another vehicle (manned vehicle) data indicating current vehicleposition, direction of progress, accuracy of current positionmeasurement, deviation from course, and angular deviation from thestipulated direction on the course (STEP 501), and determines whetherpositional deviation and angular deviation exceed stipulated values(STEP 502).

[0231] In the event that these stipulated values have been exceeded, theown vehicle is controlled to a stop by means of its vehicle controldevice 44, and an Alarm signal is transmitted to the other vehicle viainter-vehicle communication device 6 (STEP 503). Where the stipulatedvalues have not been exceeded, the own vehicle estimates a range ofpossible locations for itself (STEP 504) and also estimates a range ofpossible locations for the other vehicle (STEP 505).

[0232] Specifically, for the own vehicle, the range of possiblelocations is estimated as a path connecting a plurality of points onprearranged travel route, of width including latitude for positionmeasurement accuracy, positional deviation, and vehicle width, whereasfor the other manned vehicle, the range of possible locations isestimated as a circle centered on the current position, of diameterincluding latitude for position measurement accuracy and vehicle width.

[0233] Once ranges of possible location for the vehicles have beencomputed in this way, a decision is made as to whether the range ofpossible locations for the other vehicle interferes with the range ofpossible locations for the own vehicle (STEP 506), and in the event thatthese ranges interfere with each other, data indicating the direction ofadvance of the other vehicle is used as the basis for a decision as towhether the other vehicle is traveling in the same direction on thepredetermined travel route for the own vehicle (STEP 507).

[0234] In STEP 507, where the other vehicle is traveling in the samedirection, there exists the risk that the own vehicle will overtake theother vehicle, so the speed of the own vehicle is controlled to the samespeed as the other vehicle by vehicle control device 44 (STEP 508).Where the other vehicle is not traveling in the same direction, thereexists the risk of collision between the other vehicle and the ownvehicle, so the own vehicle is controlled to a halt by vehicle controldevice 44 and an Alarm signal is transmitted to the other vehicle viainter-vehicle communication device 6 (STEP 509).

[0235] Other Vehicle=Unmanned Vehicle

[0236] Referring to FIG. 15, an own vehicle (unmanned vehicle) istransmitted from another vehicle (unmanned vehicle) data indicatingcurrent vehicle position, position data at a plurality of points on anarranged route, accuracy of current position measurement, and deviation(STEP 601), and estimates a range of possible locations for the ownvehicle (STEP 602) and a range of possible locations for the othervehicle (STEP 603).

[0237] Specifically, for the own vehicle, the range of possiblelocations is estimated as a path connecting a plurality of points on aprearranged travel route, of width including latitude for positionmeasurement accuracy, positional deviation, and vehicle width, and forthe other unmanned vehicle, the range of possible locations is estimatedas a path connecting a plurality of points on a prearranged travelroute, of width including latitude for position measurement accuracy,positional deviation, and vehicle width.

[0238] Once ranges of possible location for the vehicles have beencomputed in this way, a decision is made as to whether the range ofpossible locations for the other vehicle interferes with the range ofpossible locations for the own vehicle (STEP 604), and in the event thatthese ranges interfere with each other, a decision is made as to whetherthe other vehicle is traveling in the same direction on the arrangedroute for the own vehicle (STEP 605).

[0239] In STEP 605, where the other vehicle is traveling in the samedirection, there exists the risk that the own vehicle will overtake theother vehicle, so the speed of the own vehicle is controlled to the samespeed as the other vehicle by vehicle control device 44 (STEP 606).

[0240] In STEP 605, where the other vehicle is not traveling in the samedirection, there exists the risk of collision between the other vehicleand the own vehicle, so the estimated times of arrival to theintersection of the arranged routes are compared, and the vehicle havingthe longer estimated time of arrival is controlled to a stop. Where thedistance to the intersection is less than 1.5 times the stoppingdistance, both vehicles are controlled to a stop (STEP 607).

[0241] To describe the processes described in FIGS. 14 and 15 in otherterms, where the range of possible locations for an own vehicle and therange of possible locations for another vehicle interfere, and the othervehicle is traveling in the same direction on the arranged route of theown vehicle, there exists a risk that the own vehicle will overtake theother vehicle.

[0242] To prevent interference with the other vehicle in such cases, inthe own vehicle, under the control of vehicle control device 44, thespeed of the own vehicle is controlled to the same speed as the othervehicle.

[0243] Where the range of possible locations of the other vehicleinterferes with the range of possible locations of the own vehicle, andthe other vehicle is not traveling in the same direction on an arrangedroute, there exists a risk of collision between the vehicles.

[0244] To prevent collision between the vehicles, where the othervehicle is a manned vehicle, the own vehicle is controlled to a stopunder the control of vehicle control device 44, and an Alarm signal istransmitted to the other vehicle via inter-vehicle communication device6.

[0245] Where the other vehicle is an unmanned vehicle, the estimatedtimes of arrival to the intersection of the arranged routes arecompared, and the vehicle having the longer estimated time of arrival iscontrolled to a stop, or where the distance to the intersection is lessthan 1.5 times the stopping distance, both vehicles are controlled to astop.

[0246] Typically, the position of the other vehicle is updated at giventime (15-second) intervals, and the size of the range of possiblelocations thereof is reduced.

[0247] Where vehicles are situated in proximity to each other, highlyaccurate position information can be obtained by SS transmission, thuspreventing any interference between the ranges of possible locations.

[0248] If by some fluke both UHF communication and SS communicationshould be disabled (inter-vehicle communication devices experiencemalfunction, the range of possible locations for the other vehicle willcontinue to expand so that the range of possible locations for the othervehicle interferes with the range of possible locations for the ownvehicle.

[0249] When a manned vehicle has completed its course and will be shutdown, it is necessary to move it to a safe area lying outside theunmanned vehicle movement area before shutting it down. At shutdown,vehicle controller 55 and communication devices 5,6 are supplied withbackup power by backup power supply 54 and continue to function, withvehicle controller 55 stopping the manned vehicle, and a signal to theeffect that “this vehicle has been shut down”, “the vehicle ID of thatvehicle”, and “position data for that vehicle” being sent to monitoringstation 20 via monitoring station/vehicle communication device 5

[0250] At monitoring station 20 the transmitted data is stored, andother vehicles are controlled so as to prevent them from entering thisposition (area) based on that position data; at the same time, thesignal to the effect that “the manned vehicle has been shut down” and“the vehicle ID of the manned vehicle” are transmitted to all vehiclesvia monitoring station/vehicle communication device 5.

[0251] Vehicles receiving this signal to the effect that “the mannedvehicle has been shut down” proceed to terminate the interferenceestimation process (i.e., calculating a range of possible locationsafter a predetermined time interval assuming movement at maximum speed)for the manned vehicle.

[0252] Whereas the present embodiment describes a vehicle interferenceestimation process that assumes the own vehicle is an unmanned vehicle,basically the same process would be used where the own vehicle is amanned vehicle.

[0253] As noted, according to the present embodiment, for long-distancecommunication there is an extended time interval (15 seconds, forexample) for position information, whereby it is possible to makeadjustments for insufficient communication capacity. In other words, theload on the communications circuit can be controlled.

[0254] Since each vehicle estimates vehicle interference taking intoaccount information pertaining to other vehicle position and receptiontime, measurement time, or transmission time, the likelihood ofinterference can be determined accurately despite the extended (coarse)time interval for position information.

[0255] To prevent interference with a manned vehicle, which may notalways travel as-planned on a predetermined prearranged travel route, anunmanned vehicle will take measures such as halting the own vehicle ortransmitting an alarm to the manned vehicle, thereby avoiding collisionor the like.

[0256] This obviates the need for the human operator to drive a mannedvehicle so as to travel as-planned along a predetermined travel route,thereby allowing the operator to travel along the prearranged travelroute on his or her own volition. Thus, the manned vehicle can beemployed efficiently for work, even in situations where both mannedvehicles and unmanned vehicles are present on the work site.

EMBODIMENT 2

[0257] This second embodiment assumes a vehicle monitoring system likethat described in the first embodiment: the arrangement of thecommunications system in this vehicle monitoring system is basically thesame as the arrangement shown in FIG. 2, the device arrangement on-boardunmanned vehicles is basically the same as the arrangement shown in FIG.3, and the device arrangement on-board manned vehicles is basically thesame as the arrangement shown in FIG. 4.

[0258] This second embodiment, however, differs from the firstembodiment in that there exists the possibility that a manned vehicledepicted in FIG. 4 will escort an “ordinary” manned vehicle (namely, amanned vehicle lacking a position-measuring device, communicationdevices, etc.) as it travels along a prearranged travel route; in thatmonitoring station 20 function is slightly modified so as to enable thisescorted travel; and in that the vehicle range of possible locationsestimation process is slightly modified.

[0259] These points of difference are described below.

[0260] Firstly, the escorting manned vehicle (the manned vehicledepicted in FIG. 4) is defined as the escorting vehicle, and the mannedvehicle being escorted by the escorting vehicle is defined as theescorted vehicle.

[0261] As this escorted vehicle (a repair vehicle, for example) lacks aposition-measuring device, communication devices, etc., while the humanoperator can visually recognize other vehicles on a large work site suchas a mining operation, unmanned vehicles cannot recognize it. Thus, ifsuch a vehicle were to travel unescorted around a large work site, therewould be a risk of collision with unmanned vehicles. Accordingly, byhaving escort vehicle escort the escorted vehicle around, the escortedvehicle may move about in safety.

[0262] The escort vehicle (manned vehicle 11 in FIG. 1, for example)comprises a mode switch for switching between a guiding mode (escortmode) in which it guides an escorted vehicle, and a non-guiding mode(non-escort mode) in which it is not guiding a vehicle.

[0263] Mode information set by the mode switch is transmitted tomonitoring station 20 via monitoring station/vehicle communicationdevice 5.

[0264] Where the mode information received from escort vehicle 11 viamonitoring station/vehicle communication device 23 indicates non-escortmode, monitoring station 20 transmits instruction data to unmannedvehicles via monitoring station/vehicle communication device 23,instructing them not to enter a range of possible locations whichincludes the current position of escort vehicle 11, calculated by aprocess described later.

[0265] On the other hand, where escort mode is indicated, the monitoringstation transmits instruction data to unmanned vehicles via monitoringstation/vehicle communication device 23, instructing them not to enter arange of possible locations which includes the current position ofescort vehicle 11, calculated by a process described later, as well as arange of possible locations which includes the current position of anescorted vehicle being escorted by escort vehicle 11, calculated by aprocess described later.

[0266] Turning now to the process for estimating a range of possiblelocations for another vehicle (manned vehicle) performed by each vehicle(both manned vehicles and unmanned vehicles), the estimation process maybe carried out by either of two methods, a circle computation method ora course computation method, which are now described.

[0267] In the present embodiment, let it be assumed that the ownvehicle, namely, the vehicle computing a range of possible locations forother vehicle, is an unmanned vehicle (unmanned vehicle 10, for example;in actual practice, it does not matter if the vehicle is a mannedvehicle or unmanned vehicle), and that the other vehicle whose range ofpossible locations is being computed is a manned vehicle {escort vehicle(manned vehicle 11, for example) only, or an escort vehicle plus anescorted vehicle (such as a repair vehicle)}.

[0268] Method 1: Circle Computation Method

[0269] On the basis of a plurality of position data for manned vehicle11 indicating its path of movement (prearranged travel route) receivedvia inter-vehicle communication device 6, unmanned vehicle 10 calculatesa circle—on the assumption of travel at maximum speed to a predeterminedfuture point in time—and assumes the area within this circle to be therange of possible locations (estimated range of motion or estimatedrange of possible locations) for the escort vehicle or the escortedvehicle.

[0270] Specifically, referring to FIG. 16, on the basis of position dataindicating the last reported vehicle position P (latest position data),the range of possible locations for escort vehicle 11 is designated tobe a circle 80 of radius r equivalent to the distance over which it cantravel at maximum speed from this vehicle position P (i.e., estimatedrange of motion).

[0271] The range of possible locations for the escorted vehicle consistsof an area (i.e., estimated range of motion) defined by circles 81, 82of radii equal to the distances traveled at maximum speed from a pointP1, lying within a predetermined distance from position P—the lastreported vehicle position for which information has been received fromescort vehicle 11—defined as the escort area, and another point P2,respectively.

[0272] Out of safety considerations during travel, the escorted vehicleis escorted maintaining a given distance between vehicles (a distancesuch that the vehicles can visually recognize each other), and thuscircles 81, 82 partly overlap circle 80.

[0273] Method 2: Course Computation Method

[0274] On the basis of a plurality of position data for manned vehicle11 indicating its path of movement (prearranged travel route) receivedvia inter-vehicle communication device 6, unmanned vehicle 10 calculatespositions on the prearranged travel route on the assumption that themanned vehicle will travel at maximum speed along the prearranged travelroute (course) to a predetermined future point in time, and assumes thearea between these positions and the last reported vehicle position tobe the range of possible locations for the manned vehicle.

[0275] Specifically, referring to FIG. 17, on the basis of position dataindicating the last reported vehicle position P (latest position data)received via the inter-vehicle communication device 6, positions 60 a,60 b on prearranged travel route 60 are calculated—assuming movement ofthe manned vehicle at maximum speed along prearranged travel route up toa predetermined future point in time—and the range of possible locationsfor the escort vehicle is assumed to be the area 90 on the prearrangedtravel route lying between these positions 60 a, 60 b and the lastreported vehicle position P (i.e., estimated range of motion).

[0276] The range of possible locations for the escorted vehicle isdetermined by computing a position on the prearranged travel routeassuming travel at maximum speed from a point P1, lying within apredetermined distance from position P—representing the last reportedvehicle position for which information has been received from escortvehicle 11—defined as the escort area, and another point P2,respectively (this position lies within area 90), designating the area91 lying between this position and points (positions) P1, P2 as therange of possible locations (namely, estimated range of locations).

[0277] Unmanned vehicle 10—which calculates a range of possiblelocations for the manned vehicle in this way—receives from monitoringstation 20 mode information and the vehicle ID for the manned vehicle,as well as appropriate instruction data for the mode information.Unmanned vehicle 10 is then managed and controlled by monitoring station20 so as to prevent it from entering the range of possible locations ofthe manned vehicle.

[0278] Specifically, when the mode of the escort vehicle (manned vehicle11) is non-escort mode, unmanned vehicle 10 is managed and controlled soas to prevent it from entering—where Method 1 is used—a range ofpossible locations 80, or—where Method 2 is used—a range of possiblelocations 90; conversely, in escort mode, it is managed and controlledso as to prevent it from entering—where Method 1 is used—a range ofpossible locations 80 and ranges of possible locations 81, 82, or—whereMethod 2 is used—a range of possible locations 90 and range of possiblelocations 91.

[0279] In other words, this means that prearranged travel routes lyingoutside of ranges of possible locations calculated in the precedingmanner are designated as permissible travel ranges.

[0280] A range of possible locations for a manned vehicle can also beestimated using a combination of the two methods. For example, Method 1can be used for long distances and Method 2 used for shorter distances.Alternatively, rather than plotting a circular range of possiblelocations using Method 1, one may plot an ellipse having greaterextension in the direction of forward advance of the vehicle from theposition of the other vehicle. That is, one may plot an ellipse havingthe direction of forward advance of the vehicle as its major axis.

[0281] When using the circle computation of Method 1, there exists arisk that the estimated future range of possible locations for the othervehicle may interfere with the own vehicle if the distance between thetwo vehicles has been shortened by passing by each other, for example.This may be avoided by employing Method 2; or by instead employingMethod 1 for long distances, while for shorter distances transmitting tothe other vehicle, by means of SS transmission, direction of advanceinformation and predicted route information in addition to positioninformation, so as to provide a more precise estimate of range ofpossible locations.

[0282] In the second embodiment the escorted vehicle is a repairvehicle, but this is not a limiting example, other examples being a dumptruck, wheel loader, hydraulic shovel, or other work vehicle lacking aposition-measuring function and communications function.

[0283] As noted, according to the second embodiment, an escort vehicle(manned vehicle) exchanges data with manned vehicles and unmannedvehicles having position-measuring devices and communication devices andwith a monitoring station, while escorting an escorted vehicle (mannedvehicle) lacking a position-measuring device and communication devices,allowing the escorted vehicle to be conducted safely about a large worksite such as a mining operation.

[0284] Since the escort vehicle travels while guiding the escortedvehicle, the need to provide all manned vehicles with position-measuringdevices and communication devices is obviated, so initial outlays can bereduced.

[0285] In the event that a position-measuring device or communicationdevice on board a manned vehicle should malfunction, makingcommunication with other vehicles and the monitoring station impossible,the manned vehicle will nevertheless be able to travel safely about alarge work site such as a mining operation, guided by another mannedvehicle whose devices are functioning normally.

EMBODIMENT 3

[0286] This third embodiment assumes a vehicle monitoring system likethat described in the first embodiment: the arrangement of thecommunications system in this vehicle monitoring system is basically thesame as the arrangement shown in FIG. 2, the device arrangement on-boardunmanned vehicles is basically the same as the arrangement shown in FIG.3, and the device arrangement on-board manned vehicles is basically thesame as the arrangement shown in FIG. 4.

[0287] This third embodiment, however, differs from the first embodimentin that the vehicle interference process is slightly modified.

[0288] Specifically, the present embodiment is premised on the ownvehicle being a manned vehicle and the other vehicles being eithermanned vehicles or unmanned vehicles, with vehicle interferenceprevented through exchange of data among these vehicles.

[0289] The process by which a manned vehicle estimates a range ofpossible locations for another manned vehicle or unmanned vehicle inorder to prevent this manned vehicle from interfering with anothermanned vehicle or unmanned vehicle is now described. There are twomethods: a circle computation method (see FIG. 6) and a coursecomputation method (see FIG. 7), which, having been described previouslyin EMBODIMENT 1, are not discussed in detail here.

[0290] Exchange of data between vehicles close enough that communicationby SS transmission is possible, and estimation by these vehicle ofranges of possible locations for themselves and for the other vehicle,are accomplished in the manner described previously in EMBODIMENT 1.

[0291] Specifically, as regards data exchange, an unmanned vehicletransmits to other vehicles position data indicating its current vehicleposition as well as a prearranged travel route in the form of positiondata for a plurality of points on the prearranged travel route. At thesame time, data indicating current position measurement accuracy andpositional deviation is transmitted to the other vehicles.

[0292] A manned vehicle, meanwhile, transmits to other vehicles positiondata indicating its current vehicle position and information concerningthe direction of advance. At the same time, data indicating the currentposition measurement accuracy, data indicating positional deviation fromthe course, and data indicating angular deviation from an indicateddirection on the course are transmitted to other vehicles.

[0293] For an unmanned vehicle, the range of possible locations isestimated as a path connecting a plurality of points on a prearrangedtravel route, of width including latitude for position measurementaccuracy, positional deviation, and vehicle width. For a manned vehicle,on the other hand, the range of possible locations is estimated as acircle centered on the current position, of diameter including latitudefor position measurement accuracy and vehicle width.

[0294] In manned vehicles, ranges of possible locations for theaforementioned manned vehicles or unmanned vehicles, namely, theinformation depicted in FIGS. 6, 7, 16, and 17, is displayed on thedisplay screen of a display device 52 a.

[0295] In the present embodiment as well, the vehicle interferenceprevention process is basically the same as the process described withreference to FIGS. 8-12, 14, and 15.

[0296] However, in this case own vehicle=“unmanned vehicle” is redefinedas own vehicle=“manned vehicle”. STEP 406 of the process shown in FIG.12 now consists of lighting the red lamp of indicator light 52 b todisplay the warning “Stop: approaching unmanned vehicle.” That is, whenthere is interference between the range of possible locations—computedfor a predetermined time in the future (5 seconds for example)—for avehicle that cannot communicate through SS transmission (an unmannedvehicle, for example) and the range of possible locations—computed for apredetermined time in the future (5 seconds for example)—for the ownvehicle (manned vehicle), the red lamp in the own vehicle lights up toprovide a warning display.

[0297] The control process by SS transmission in FIGS. 14 and 15 alsodiffers slightly, and accordingly is described hereinbelow. In thisprocess, there are two procedures, depending on whether the othervehicle is a manned vehicle or an unmanned vehicle; the case of a mannedvehicle is described first, followed by that for an unmanned vehicle.

[0298] Other Vehicle=Manned Vehicle

[0299] Referring to FIG. 18, an own vehicle (manned vehicle 11, forexample) receives from another manned vehicle (manned vehicle 13, forexample) data indicating current position, direction of progress,accuracy of current position measurement, deviation from course, andangular deviation from the stipulated direction on the course (STEP701), and estimates a range of possible locations for itself (STEP 702)and a range of possible locations for the other manned vehicle 13 (STEP703).

[0300] Specifically, the range of possible locations for own vehicle 11is estimated as a path connecting a plurality of points on a prearrangedtravel route based on course data, of width including latitude forposition measurement accuracy, positional deviation, and vehicle width.The range of possible locations for the other manned vehicle 13 isestimated as a circle centered on the current position, of diameterincluding latitude for position measurement accuracy and vehicle width.

[0301] Once ranges of possible locations for the vehicles have beencalculated in this manner, a determination is made as to whether therange of possible locations for the other vehicle interferes with therange of possible locations for the own vehicle (STEP 704), and wherethe ranges of possible locations interfere, a determination is made asto whether the other vehicle is traveling in the same direction on theprearranged travel route for the own vehicle (STEP 705).

[0302] In STEP 705, if the other vehicle is traveling in the samedirection, there is issued Warning information to the effect that thereis a risk of overtaking the other vehicle (STEP 706), whereas if theother vehicle is not traveling in the same direction, there is issuedAlarm information warning of the risk of collision with the othervehicle (STEP 707).

[0303] Specific examples of Warning information are, for example, adisplay on the display screen of display device 52 a to the effect that“there is a risk of overtaking the other vehicle,” or lighting up of theyellow lamp of indicator light 52 b. A combination of the above is alsopossible.

[0304] Specific examples of the above-mentioned Alarm information wouldbe, for example, a display on the display screen of display device 52 ato effect that “there is a risk of collision with another vehicle”, forexample; lighting up of the red lamp of indicator light 52 b; or abuzzer sound emitted by an alarm buzzer 52 c. Combinations of the aboveare also possible.

[0305] Other Vehicle=Unmanned Vehicle

[0306] Referring to FIG. 19, an own vehicle (manned vehicle 11, forexample) receives from another unmanned vehicle (unmanned vehicle 10,for example) data indicating current vehicle position, position data ata plurality of points on an arranged route, accuracy of current positionmeasurement, and deviation (STEP 801), and estimates a range of possiblelocations for itself (STEP 802) and a range of possible locations forthe other unmanned vehicle (STEP 803).

[0307] Specifically, for the own vehicle 11, the range of possiblelocations is estimated as a path connecting a plurality of points on aprearranged travel route, based on course data, of width includinglatitude for position measurement accuracy, positional deviation, andvehicle width. For the other unmanned vehicle 12, the range of possiblelocations is estimated as a path connecting a plurality of points on aprearranged travel route, of width including latitude for positionmeasurement accuracy, positional deviation, and vehicle width.

[0308] Subsequently, processes analogous to those described previouslyin STEPS 704-707 are performed (STEPS 804-807).

[0309] To describe the processes described in FIGS. 18 and 19 in otherterms, where the range of possible locations for another vehicleinterferes with the range of possible locations for an own vehicle and,and the other vehicle is traveling in the same direction on the arrangedroute of the own vehicle, there exists a risk that the own vehicle willovertake the other vehicle. To prevent interference with the othervehicle in such cases, the Warning information described earlier isissued in the own vehicle.

[0310] Where the range of possible locations of the other vehicleinterferes with the range of possible locations of the own vehicle, andthe other vehicle is not traveling in the same direction on the arrangedroute for the own vehicle, there exists a risk of collision between thevehicles. To prevent collision between the vehicles, the Waringinformation described earlier is issued in the own vehicle.

[0311] As noted, according to EMBODIMENT 3, in a manned vehicle, therelative positional relationship of the own vehicle (manned vehicle) andanother vehicle, as well as the range of possible locations for thisother vehicle, are displayed on a screen in the manned vehicle, therebyallowing the human operator of the manned vehicle (own vehicle) toascertain before the fact the likelihood that, on the current course,the vehicles will interfere, for example, so that interference betweenthe vehicles can be avoided.

[0312] Even in the event that a human operator should fail to notice theinformation displayed on the screen display, since indicator light 52 blights the red lamp and the warning buzzer 52 c sounds, the operatorwill be apprised of the situation and can manually stop the vehicle ormove it to a safe location in order to avoid the risk of a collision.

[0313] Further, where operations are being carried out at a minesituated in the high mountains, etc., where, for example, visibility isimpaired by mist, since the relative positional relationship of the ownvehicle (manned vehicle) and another vehicle are displayed on a screen,a human operator can ascertain before the fact the likelihood thatvehicles will interfere, for example, so that interference between thevehicles can be avoided.

What is claimed is:
 1. A vehicle interference prevention device forpreventing interference among vehicles where a plurality of vehicles aretravelling over a travel route, wherein each of the plurality ofvehicles comprises: measuring means for measuring a position of its ownvehicle; communication means for exchanging with other vehicles, in awireless communications format, position information indicating theposition of its own vehicle, as measured by the measuring means;estimating means for estimating a likelihood of interference between itsown vehicle and other vehicle on the basis of position information forthe other vehicle received via the communication means, time informationindicating a reception time at which the position information isreceived, and the position information for its own vehicle; and controlmeans for performing a preset control routine in the event thatinterference is predicted by the estimating means, so as to avoidinterference with the other vehicle.
 2. The vehicle interferenceprevention device according to claim 1 , wherein the communication meanscomprises: means for transmitting and receiving vis-á-vis othervehicles, in a wireless communications format, position informationindicating vehicle position, as measured by its own measuring means, andtime information indicating a time of measurement of the vehicleposition or time information indicating a time of transmission of theposition information; and the estimating means comprises: means forestimating the likelihood of interference between its own vehicle andother vehicle on the basis of the position information for the othervehicle received via the transmitting/receiving means, the timeinformation for either the measurement time or the transmission time,and the position information for its own vehicle.
 3. The vehicleinterference prevention device according to claim 1 or 2 , wherein theestimating means comprises: first estimating means for estimating, onthe basis of the position information and the time information for othervehicle received via the communication means, a future position of theother vehicle at a point in time coming a predetermined time intervalafter the time, or a range of movement of the other vehicle; secondestimating means for estimating from its current position on the basisof position information for its own vehicle a future position of its ownvehicle at a point in time coming a predetermined time interval later,or a range of movement of its own vehicle; and decision means fordeciding if the future position or range of movement of the othervehicle estimated by the first estimating means overlaps the currentposition or future position of its own vehicle estimated by the secondestimating means.
 4. The vehicle interference prevention deviceaccording to any of claims 1, 2, or 3, wherein each of the plurality ofvehicles further comprises processing means that, during power-on of itsown vehicle, notifies other vehicle that its own vehicle has started up,and in the event that no response to the notification is received by itsown communication means, makes a determination that the communicationmeans of the other vehicle is not functioning normally, and places itsown vehicle in standby mode at its current position.
 5. A vehicleinterference prevention device having an unmanned vehicle comprisingvehicle position-measuring means for measuring a position of its ownvehicle and traveling over a travel route based on predeterminedinstruction data, a first manned vehicle having position-measuring meansfor measuring a position of its own vehicle, and a second manned vehicletraveling over the travel route guided by the first manned vehicle;wherein the unmanned vehicle and the first manned vehicle each comprisescommunication means for transmitting and receiving predeterminedinformation among themselves; the first manned vehicle transmits to theunmanned vehicle via the communication means a mode which is either aguiding mode wherein the second manned vehicle is guided, or anon-guiding mode wherein the second manned vehicle is not guided; andtransmits to the unmanned vehicle via the communication means positioninformation indicating the vehicle position determined by theposition-measuring means; and the unmanned vehicle, in the event thatthe mode received via the communication means is the non-guiding mode,is controlled, on the basis of the position information from the firstmanned vehicle, in such a way as to avoid entering an area of a givenrange that includes a current position of the first manned vehicle;whereas in the case of the guiding mode, it is controlled, on the basisof the position information from the first manned vehicle, in such a wayas to avoid entering the current position of the first manned vehicleand an area of a given range lying to a rear of the first mannedvehicle.
 6. The vehicle interference prevention device according toclaim 5 , further comprising a monitoring station havingtransmitting/receiving means for transmitting and receivingpredetermined information to and from the unmanned vehicle and the firstmanned vehicle; and the monitoring station further comprises means fortransmitting to the unmanned vehicle via the transmitting/receivingmeans instruction data designating as a permissible travel range overwhich travel is permitted an area on the travel route such that the mostrecent position of the unmanned vehicle, based on the positioninformation measured by the vehicle position-measuring means andreceived via the transmitting/receiving means, does not interfere with apredicted range of motion for the first manned vehicle, as calculated onthe basis of the most recent position information for the first mannedvehicle received via the transmitting/receiving means.
 7. The vehicleinterference prevention device according to claim 6 , wherein thetransmitting means, in the event that the first manned vehicle iscurrently in the guiding mode, excludes from the permissible travelrange a predicted range for the second manned vehicle that is obtainedon the basis of the position information for the second manned vehiclebased on the position information for the first manned vehicle, andtransmits to the unmanned vehicle instruction data designating an areaof this range as a new permissible travel range.
 8. The vehicleinterference prevention device according to claim 5 , wherein theunmanned vehicle comprises: measuring means for measuring the positionof its own vehicle; decision means for deciding, on the basis of theposition information from the first manned vehicle received from thecommunication means and position information indicating the position ofits own vehicle as measured by the measuring means, whether its ownvehicle poses interference with the first manned vehicle or with an areaof a predetermined range extending from the position of the mannedvehicle; and control means that, in the event that the decision meansdecides that interference is present, halts or decelerates its ownvehicle.
 9. A vehicle interference prevention device for preventinginterference among a plurality of vehicles, including at least onemanned vehicle, as they travel along a travel route, wherein each of theplurality of vehicles comprises: measuring means for measuring aposition of its own vehicle; and communication means for exchanging withother vehicles position information indicating the vehicle positionmeasured by the measuring means; and the manned vehicle comprises:processing means for calculating relative positional relationship of itsown vehicle and other vehicle on the basis of position information forthe other vehicle received via the communication means, and positioninformation for its own vehicle; and notifying means for notifyingpredetermined information depending on the relative positionalrelationship calculated by the processing means.
 10. The vehicleinterference prevention device according to claim 9 , wherein the notingmeans comprises display means for visually displaying the relativepositional relationship.
 11. The vehicle interference prevention deviceaccording to claim 9 or 10 , wherein the notifying means provides awarning in the event that the relative positional relationship is suchthat its own vehicle and the other vehicle are in close proximity andinterfering.
 12. The vehicle interference prevention device according toclaim 9 , wherein the plurality of vehicles further comprises:transmitting/receiving means for exchanging with other vehicle timeinformation indicating either of a time at which the vehicle positionwas measured by the measuring means of its own vehicle, or a time atwhich position information indicating this vehicle position wastransmitted; and all of the manned vehicles including at least onemanned vehicle further comprise: range estimating means for estimating,on the basis of position information for other vehicle received via itsown communication means, and either time information for this positioninformation indicating the time at which the position information wasreceived by the communication means, or the time information having beentransmitted by the other vehicle, a range of movement of other vehiclefrom a position based on the position information to another position ata point in time coming after a predetermined time interval has passed;and display means for displaying the relative positional relationshipcalculated by the processing means, and for displaying the range ofmovement estimated by the range estimating means for the other vehiclein the positional relationship.